Motor control.



No. 832,745. PATENTED OCT. 9, 1906: J. S. PEVEAR. MOTOR CONTROL.

AI PLICATION IILED AUG 10, 1904.

2 SHEETS-SHEET l Wimesss w lrwenfor.

9, i/(M' Jesse S.Pevear.

PATENTBD OUT. 9, 1906 J. S. PEVEAR. MOTOR CONTROL.

APPLIGATIOH FILED AUG.10, 1904.

2 SHEETSSHEET 2 lflVIRTOTT Jesse S Pevear.

W m csses UNITED STATES PATENT OFFICE.

JESSE s. BEVEAR, or 'SQHENECTADY, NEWYORKZ ASSIGNOR To GENERAL ELECTRIC COMPANY, A CORPORATION or NEW YORK.

MOTOR CONTROL.

Specification of Letters Patent.

Patented Oct. 9, 1906.

Application filed August 10, 1904. Serial No. 220,166.

I-t is sometimes desirable to employ a high-" tension alternating current over a portion of the length of an electrical railwayas, for

instance, in the country or over private rights of'way,-a-nd to employ low-tension direct current over other portions, as in city streets;

Certain types of motors'as, for instance, the weil-known series motorma'y .be' designed for operation on either alternating or direct current. When a transformer is employed for reducing the alternating-current voltage to the proper amount for impressing upon the motor-terminals, switches are required on the car for connecting the trolleyto the primary of the transformer ordirectly to the motors with the transformer cut out of circuit, according as the operation is on alternating or direct current. Furthermore, it is important that both of these switches shall not be closed at the same time, since damage would result either the motor- The above-mentioned change in. the circuits is not all that is required, since'if a series motor is designed for operation upon a certain alternating-current voltage and is then connected to a direct-current source of the same voltage the motor will be heavily overloaded, since the motor then possesses no self-induction, and the entire impressed voltage must be balanced by the counter electromoti've force developed in the motor-armaturethat is, both the current-flow and the speed will increase.

instance, when two hundred volts alternating and threehundred volts direct are. emvplo ed per motor-the overload would be stilF more serious. Co uently in changing from alternating to direct currents the motor-field shouldbe at A the counter clean-emotive force per to the transformer or to system embodying When the direct-. 'current voitage, is not equal to the alternating-current voltage,- but is greateras,. for.

ened, so-as toampere. This can beaccomplished in a simple manner by connecting the two portions of the field in parallel for alternating current and in series for direct current.

The above s stem, in its broadest aspects, is fullv set fort in Patent N o. 7 83 ,124, ranted Februa 21, 1905, on application ed by Maurice M1lch, and in Patent No. 808,778,

granted on January 2, 1906, on an application filed by William B. Potter, a development is disclosed i In some of its aspects the present inven-.

tion relates to improvements in said system, one of the features of the present invention residing in ya novel arran ement of the switches for connecting eit ier the transformer or' the motors to the trolley, whereby it is impossible'that both. should be closed at the same time.

Another feature of my invention consists in-so arran 'ng the switch for making the chan e t emotor-fields andalso the two switc es mentioned above for connecting the trolley to transformer or to motors direct that the, switches are interlocked with each other and that the switch for varying the motor-field cannot be moved except when both of the other switches'a're in their off position.

Other features of my invention will appear from the following specification and accompanying drawings in which- Figure 1 shows diagrammatically a control my invention; Fig. 2 shows the construction of the switches for connecting the trolley to the transformer or motors direct, and Fig. 3 shows the top of a casing for a switchwhich'varies the field stren th of themotors;

Re errin first to Fig. 1, M M M M repre: sent four 4% nected in two groups of' two motors connected in series. C represents the usual con-' troller. R represents the reversing-switch.

b means of which the relative connections riving-motorsfor a vehicle con-- ICC o fields and armatures may be reversed to reverse the direction of rotation of the motors.

The fieldofeach motor is shown divided into two arts which are connected to the switch E, w uchl' shall hereinafter call'the fcom parallel.

mutating-switch and which acts to connect the two portions of the 'field in series and in switch C are connected-{through the commutating-switch E, to-the secondary of the transformer T or to the switch D accordin as to which osition the commutating-switc E is in. T e primary of transformer T is connected to switch -A. T representsv the trolley-or other source of current, which is I connected both to switch D and to switch A.

Thus if switch D is closed trolley T. is connected directly through the commutatingswitch D to the motor-circuits, while if switch A is closed the trolley T is connected, through the primary of transformer T, to

earth. The two switches A and D are shown mounted on a single 0' crating-lever indicat ing diagrammaticallj t at when one switch is opened the other is closed. m represents an auxiliary motor for driving an air-compressor and is connected to contacts on the conirnutatingswitc'h E. 1" indicatesa resistance in series with the motor m. 9 represents a governor for the motor m, and 8 represents a switch by which the circuit of motor m may be opened or closed. Lre presents lam s, and

' H heating-coils, one circuitsterminal 0 which is connected to the commutating-switch E switch commutating-switch mutating-switch E is in the position to bring I and. the other terminal to a terminalof the compensator t. The other terminal of compensator t is connected to a 'contact'offcommutating-switch E, while an intermediate tapis connected to earth. I I I The aperation is as followsj Assum'e that is closed, therebly and connecting trolle to contact e of the movable contacts on the lines dd in en-; gagement with the'stationary contact- 7 ers; "assume that reversing-switch 'R is in orward positionthat is, with thefmovable contacts on the line f and 17' in enga ement' tact a, resistance I, contacts 1" and con- I the fields of motors with the stationary contactefingers, t en let the controlling-switch C be moved to its first p alsition, as indicated by the first dotted line. I

e circuits are then as followsi' t'rolley T, switch D,- coiitactfeifl'contact e 1, contact e, contact e, blow-out coil B, contact (2, con-' tactsf and fl, armature of motor I Carmature of motor M, contacts f and f, canthus connected all miseries-with each other, Twith, the two vportions of the field of each mo- The motors and the controlling motors M and M The current then unites, passin t'hrough contacts, contact 10", con- 'tactsj j otmot r M, armature of motor M "contacts '3 and f 'contactsf and f Here the curopening switch A assume that 'com-" in cross-section. to contain oil, in-w'hic'h are suspended, the 1 0 tor seriesi Furthercircuits may readily be tracedthrough the lamps and heaters and through the air-compressor motor; but since these form no part of the present invention the will not be described in detail.

As contro ling-switch O is moved through its other positions resistance I is cut out of circuit ste y ste then the motors are connected in paralle with the resistance 1, reinserted, and the resistance is then againcut out of circuit, this being the usualarrangement of seriesin circuits need not be traced here in detail, but will be evident from an inspection of the drawings. Now if switch D is 0 en" and commutating-switch E is moved to ring the movable contacts on the line a a into engagement with the stationarycontactmembers and if the switch A is then closed the -following circuit will be established: The trolley'T is connected directly to the primary of transformer T. Starting from the right-hand terminal of'the secondary winding of transformer T the motor-circuit'runs asfollows: contact e,'contact e", contact e, contact re, contact '0, contact c, resistance 1, contacts f a and f c'ontactsf and f throu h armature ofmotor M armature of motor contacts f and f 7', contacts f and f Here the current divides, part going through the lower Ihalvesof'the field of the motors. M and M aiid through contacts e and e? andthe other part going throu h contacts e and e? andt-hroug the upper alves of the field of and f contacts f 3, and f al'ti nat-ure rent divides, part assin'g through contact e and contact ean the upper halves of the fields of motors M and Mto ground and the other half passing throu h the lower .halves. of fields ofmotors M an M contact a, contacte to'ground. The motors are thus connected'insei'ies with each other with all the resistance in circuit; but the parts of each field are in parallel with each other. Thus the "motors are properly connected for operatingon alternating current. The lamp and 1 15 heater and compressor motor-circuits may also be'readily traced, these circuits also passingrthrou h the-commutator-switch. I he utility and peculiar advantages of the present invention, which will now be de- 120 scribed, will now be more apparent in view f fthe requirements of the system just set roan, Referring to Fig. 2, the operating mechanismand the means for preventing a simultaneous closing of the switches D and A- '1 a 5 ,will be described and explained. Since the two' switches are alike, a descri tion of one will suffice for both. I The switc' D is shown 1 represents a pot adapted parallel controlling-switches. These changes the in 10.

stationary terminals 2 2. 3v represents a movable contact adapted when in the position shown to engage the stationary contacts. The movable contact 3'is carried by srod 4, which is vertically movable through an insulated bushing -6. When the rod 4 is lowered, the switoh is closed, and when it is raised the switch is opened. The rod 4 is connected by an arm 7 to a. vertically-movablerod 8, the lower end of which is secured to one arm of the bell-crank lever 9. This bell-crank lever, which. is pivoted at 5, car rise on its Ot-hQI'flJ'IUJL pin 10, engaging a. slot in the pivoted link 11. The pivoted link 11 is carried b the member 12, which is secured to' the sha t 13. At'a point-near its other end the shaft 13 is flattened or formed square for a portion of its length, as indicated in dotted lines, so as to form a head 130, which engages with the outer face of the operatinghandle 14, which fits upon the flattened or squared portion of the shaft. By means of the operating-handle the shaft 13 and the member 12 may be rotated. so as to move the pivoted links 11 and 15. The link 15 engages a pin 17 on the hell-crank lever 16, the other'end of which engages the operatingrod 180i the switch A. The two bell-cranks 9 and 16 are connected by tension-spring 19, which tends to pull the two ends of the bell-cranks together. The bell-crank 16 in the positionillustrated abuts against a sto (not shown,) while the bell-crank 9 is held in the position shown by the link 11 engaging T e o oration is as follows: If handle 14 is moved 1 tralposition, as indicated by dotted lines, the member 12 will be rotated, moving link 11 toward the rightand allowing the bell-crank '9 to be rocked big spring 19, raising rod 8 and opening switch Bellcra-nk 16will not be moved during this operation on account of the lostrnotion connection between it and thelpivoted link and will he held in the position shown by the spring 19. the motion ofhendle 14 is con sinned to its other exme position, bell-crank 9 will he left in the.

m, cell-crank 16 so as to lower rod and cl' s vitcli. The member 12 and the l' i and 15 act as toggle-joints to give a closing pressure and to lock th switcl i pcion against the spring tension. Both. switches are normally open. Gilly one switch at a. time can he closed by a inove ment of the handle in one direction or the other from itscentral position. It will he seen that it is the spring 19 which returns i each switch to its open position when handle 14 is moved to its oft position. In orderto guard against both switches being closed-at once, because of thehreaking or spring 19 when one switch isclosed and the handle is moved to close the'other, I provide the men's rorn the position shown to its cention against its stop and link will push 16, respectively.

A hen handle 1% is passes its off position, the member 22 will engage the post and will rock the bellcrank lever 9 so as to open the switch D. Since the post 1.3 and the end of member 22 are rotating around difierent centers, the post 23 will move out of the path of member 22 after switch D is opened. Thus, the post '24 is clear of the member 22 when the bellcrank lever 16 is in the position shown; The handle 14 cariies a stop 20, (shown in dotted lines,).which presses against s rings 21 cariied by the flange 21. T his range serves to prevent the withdrawal oi the handle 14 roni the shaft 13 in any position except the off position, and the springs hold the handle yieldingly in its running positions. At the off position the flange is cut away, shown, and the handle may be withdrawn.v Consequently both switches -nnst be open in order to remove the handle. The commutstingswitch. E, the top of which is shown in Fig. 3, is provided with no handle of its own; but its shaft 27 is shaped to be engaged by the han dle 14 of the switches D and Consequently in'order to move the commutating switch D from one position to the other it is necessary, to bring handle 14 to its oil position, opening switches D and A, in order that the handle may be withdrawn and applied to inechanisrn Accoic I" the particular cost of parts shown;

' .0 cover a l gle handle for saidswitches, and operative the in te: coking connections between said handle and said switches wherebyone of said switches only-is either direction.

moved by the movement of said'handle in In combination,, two' normally en switches, ahandle, operative onnectlons' etweenj said handle and said switches whereby the movement of said handle in either direc tion'moves one of said switcbs to c'osed position, and means carried by said handle for positively engaging said switch if said switch does not open when said handle is moved in .the OPPOSltO direction to close the other switch.

j 3. In combinatidn, two switches, aspring normally holding said switches open, a hantension of sa d spring, and means carried by 4'. In combination, two normally the handlefor positively en aging and -open-.

ing saidswitch if said switc' is not returned f to ofl position by said spring-when said handle is movedm the opposite direction to close the other switch.

0 en switches, a handle, operative connections etween said handle and said switches whereby the movement of said handle in either directron moves one of said switches to closed 'po- -sition, and a member carried by one of said switches and arranged to be moved into the path of said handle-.when .said switch is tension of said holding means, and a member carried by one of. said switches and arranged to cbemoved into the path of said handle when said switchis moved to its closed position.

6.- In combination,-a plurality of motors ada tedfor operation on either alternating or irect current a switch adapted to con;- nect-said motors ior operation on' alternating current, a second switch ada ted to connect said motors. for operation on irect current, a handle, operative connections between said handle and said; switches whereby the movement of said handle in either direction closes.

one of said switches, means for preventing the withdrawal (if. said handle exceptwhen both of said switches are in ofi'positlomjandia a third switchin the motor-circuit arranged ,to be operated by said handle independentla,

of the other switches.

. seams I7. In. combination, a plurality df motors ada tedfor operation on either alternating or.

-- connect said motors for operation on alternatingzand dlrect current respectively, a single operating-handle therefor, means for prewhen said. switches are both open, and a switch adapted to vary the field strength of said motors and arranged to be operated by said handle. independently of the other switches.

-8. In'combination, a-plurality of motors ada ted for operation-on either alternating or irect'current, two switchesadapted to connect said motors for operation on .alte r nating and direct :current respectively, a sin 9. In combin t1on,. a source of current 1 supply, a translating device,-'two independent groups of switchedtheactuating of one member of each of; which serves tobring the source of'current-supply into operative relation with the translating device, a single opsaid switches, and. means for p'reventin the switches when it isflin a position other than its osition.

10. In combination a source of currentsuppl a translating device, a group of two switc es anda third independent switch the actuating of the thirdjswitch' and one oi the other's serving tolbringthe source of currentsupply into. operative relation with the translating device, and; means. for preventing the operation of the thirdswitch except when the other'two are in their :ofl position.

11.1 In combinationi a source of cur-fr?- sup a'tr ating evice, a grou o o 'swit cfes. and third independentswilch the actuating of the third switch and one oi the others serving-tobring. the source 'of currentsupply intooperative rielation to the translating device a common handle for operating said switches, and means for preventing the a plication-of thehandle to t e third switch w lien one ofthe other switchesis in a position other than its .ofif position 1 In; witness whereof I have hereunto set my handthis'4th day of Angst, 1904.

BENJA'MINIB.

HELEN ()aronn gle operating-handle therefor, means forpre-.. venting the -,withd.r'awal of said handle except when" said switches are both open, and a lrect current, twoswitches adapted to a 1 venting the withdrawal of said handle except crating-handle adapted to beapplid to-all of withdrawal of said h ndle from one o the 

